RU2635955C2 - Method and device for controlling at least one brake damper - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: method for controlling a brake damper (20) is carried out in the internal combustion engine (1). At least one brake damper (20) is located in the exhaust path pressurized by means of a turbocharger (2), (3) operating on the exhaust gases of the internal combustion engine (1). The engine (1) is equipped with at least one cylinder and a valve timing mechanism with an auxiliary brake function. The method consists in that at least one exhaust valve can be moved to the intermediate opening position with the exhaust gas back-pressure created by the brake damper (20) and also communicated with the pressurizing line (6) connected to the turbocharger compressor (2a), (3a). To the pressurizing line (6), an exhaust gas recirculation line (16) is joined, connected to the exhaust path upstream of the brake damper (20). The exhaust gas recirculation line (16) is controlled by the exhaust gas recirculation valve (15). The brake damper (20) even in case the internal combustion engine (1) is working in the combustion mode is controlled for a certain increase in the exhaust gas back-pressure. The exhaust gas back-pressure in the internal combustion engine (1) working in the combustion mode is constantly kept below the threshold value, which excludes the activation of the auxiliary braking system (EVB). A device for implementing the method is disclosed.

EFFECT: increasing the exhaust gas back pressure.

15 cl, 1 dwg

Description

The present invention relates to a method for controlling at least one brake flap in an exhaust path of an internal combustion engine with an exhaust gas turbocharger, in particular for an industrial vehicle, according to the preliminaries of claim 1, and also to a device for implementing such a method according to the restrictive part of claim 9 of the formula.

As you know, the engine braking of a four-stroke internal combustion engine with the brake flap closed in the exhaust tract is further enhanced by the fact that due to the intermediate opening of the exhaust valve, a decompression brake action is applied to it, which, for example, is initiated by increasing the exhaust back pressure, with the effect on the valve gas distribution mechanism of an internal combustion engine. Such auxiliary braking systems, also known as EVB (exhaust brake valve), are described, for example, in EP 0736672 B1 and EP 1526257 A2. DE 10 2008 032774 A1 describes a solution with a hydraulic action on the valve timing mechanism, whereby with a temporary very high backpressure of the exhaust gases, it is necessary to prevent unwanted operation of the EVB system (valve jump) in a running warm internal combustion engine.

In internal combustion engines with exhaust gas aftertreatment devices, such as catalytic converters, diesel dust filters, etc., and for a certain effect on the fuel combustion process in an internal combustion engine, devices are used to realize exhaust gas recirculation, partly with a high degree of exhaust gas recirculation gases. The achievable degree of recirculation, among other things, depends on the pressure ratio between the boost pressure of the internal combustion engine and the exhaust pressure. This pressure ratio can also be influenced, for example, by means of a controlled throttle valve in the boost pipe of the internal combustion engine.

The objective of the invention is to propose a method and apparatus by which an improved, in particular for non-stationary use, operation of an internal combustion engine in a turbocharged internal combustion engine of the indicated type could be achieved.

This problem is solved by signs of independent claims. Preferred modifications and embodiments of the invention constitute, respectively, the subject of their dependent dependent claims.

According to the invention, it is proposed that the brake flap in the exhaust path also in the heated internal combustion engine is controlled in a predetermined manner to increase the exhaust back pressure, and the exhaust back pressure is constantly kept below a threshold value that prevents the auxiliary braking system (EVB) from working. The solution proposed in the invention allows to a certain extent, without additional design costs, to provide a targeted and responsive increase in exhaust backpressure in an engine operating in a combustion mode by an amount providing an increased degree of exhaust gas recirculation. Thus, the brake flap in at least a largely closed state, along with the EVB system, in the forced idle mode controls the engine braking process, and in the engine operating in the combustion mode it controls only a partial increase in pressure that does not initiate the EVB system to trigger in the exhaust tract. Due to this, if necessary, the throttle valve described above in the boost pipe can be excluded from the design, and the degree of exhaust gas recirculation, in addition to the exhaust gas recirculation valve, can only be regulated by modulation of the exhaust backpressure. In addition, by controlling the brake flap in a combustion engine operating in a combustion mode, the process of heating it up when starting in a cold state can be accelerated.

At least one brake flap can be located upstream from the turbine of at least one exhaust gas turbocharger, which, in addition to a quick response to backpressure control, provides improved operation of the exhaust gas turbine and also unloads it from large exhaust backpressures.

In a further preferred embodiment of the method according to the invention, a pressure sensor may be provided in the exhaust path upstream of the brake flap, the signals from which are sent to the control unit for controlling the brake flap. The pressure sensor provides accurate pressure measurement and control and can thus reliably counteract the dangerous pressure peaks that occur during transient operation of the engine.

In addition, with the help of a pressure sensor, an additional protective function of the engine can be controlled in an advantageous way, in which if the exhaust gas back pressure is too high, despite the open brake flap, a controlled decrease in boost pressure and / or decrease in the amount of injected fuel is carried out, which leads to a rapid decrease pressure in the exhaust tract.

In addition, a pressure sensor can also be provided in the boost line, the signals from which are sent to the control unit for the brake flap, it being preferable that the signals of both pressure sensors in the exhaust tract and in the boost line are logically connected in the control unit for a controlled installation of a certain pressure difference. Thus, the pressure values upstream and downstream of the combustion chamber of the engine are compared and the brake flap is adjusted accordingly to establish a certain pressure drop.

Alternatively to the pressure sensor in the exhaust tract, or preferably in addition to it, the brake flap in the engine operating in the combustion mode can be controlled depending on the operating parameters of the internal combustion engine and / or depending on the instructions of the vehicle control processor. It is preferable that the data required for this are already registered in the engine control unit and / or in the car control processor and only require a brake damper in the engine operating in the combustion mode of modification.

Thus, in accordance with these data, a characteristic for controlling the brake flap can be recorded in the engine control unit in accordance with these data, and the brake flap can be accordingly controlled. In particular, such parameters as: temperature of the internal combustion engine, amount of injected fuel, number of revolutions of the internal combustion engine and its load value, which can be automatically controlled in the engine control unit, can be recorded as operating parameters for controlling the brake flap, among others in such a way that a given degree of exhaust gas recirculation can be carried out, and, if necessary, a quick warm-up of the internal combustion engine Ania. In addition, in the control of the brake flap by the vehicle control processor, the position of the accelerator pedal and / or the included gearbox stage and / or driver's command can be recorded among other things and used to control the brake flap.

In addition, in particular, to implement the method described above, a device is provided in which the brake flap located in the exhaust duct is located upstream of the exhaust gas turbine of an exhaust gas turbocharger and can be driven by an engine control unit also operating in a combustion mode of an internal combustion engine for the controlled installation of a given exhaust backpressure. The actuation of the brake flap can be carried out pneumatically, hydraulically or particularly preferably electrically by means of an appropriate servomotor.

In addition, the internal combustion engine may have a register pressurization system with a high pressure turbocharger and a low pressure turbocharger, the brake flap being preferably located in the exhaust path upstream of the exhaust gas turbine of the high pressure turbocharger.

In addition, in the case of an internal combustion engine with several cylinders, two exhaust manifolds may be provided with separate exhaust passages to the exhaust gas turbine, and one exhaust damper may be installed in both exhaust ducts, which are preferably synchronously actuated by means of a servomotor. To do this, either one pressure sensor in both exhaust channels can be used, or, using a connecting line, only one pressure sensor for both exhaust channels.

In addition, one exhaust gas recirculation line can be branched from both exhaust channels upstream of the brake flaps with an exhaust gas recirculation valve integrated in each of them, which are brought together into at least one exhaust gas cooler and connected to the boost line. By means of separate exhaust gas recirculation lines with integrated exhaust gas recirculation valves (for example, electrically controlled pulse (stroke) valves), an even more precise control of the corresponding degree of exhaust gas recirculation can be provided.

If necessary, for even more precise control of the degree of exhaust gas recirculation in the boost line, a pressure sensor may be located downstream of the means for influencing the boost pressure. This can be, for example, a ventilation duct from the boost line to the exhaust path downstream of the brake flap. However, it is preferred that a throttle valve or a throttle valve known per se be used for this.

Finally, at least in the exhaust gas recirculation line and / or in the boost line, temperature sensors can be located which are connected to the engine control unit for controlling the brake flaps, respectively, for indirectly affecting the exhaust gas recirculation and which, for example, at very high temperature values through the control (regulation) of the brake flaps help to reduce the exhaust back pressure.

An example embodiment of the invention is described below in detail using the attached block diagram of a four-cycle exhaust gas turbocharged internal combustion engine, a motor brake device with a brake flap and an exhaust gas recirculation device.

The block diagram shows only approximately the self-igniting six-cylinder four-stroke internal combustion engine 1 for industrial vehicles, which is shown only to the extent necessary for understanding the present invention. Unless otherwise indicated, the internal combustion engine 1 may be an engine of known design.

The internal combustion engine 1 is pressurized by means of an exhaust gas turbocharger 2 low pressure and an exhaust gas turbocharger 3 high pressure, and the compressors 2a and 3a connected one after the other direct combustion air to the internal combustion engine 1 through charge air coolers 4, 5 and line 6 boost.

Compressors 2a and 3a are driven by exhaust gas turbines 2b and 3b, which are included in the exhaust duct of the internal combustion engine 1. Moreover, bypass devices for regulating boost pressure, if necessary, are not shown.

The exhaust path, as shown, is composed of two exhaust manifolds 7, 8, two separately leading to the exhaust gas turbine 3b of the exhaust line 9, 10 leading further to the exhaust gas line 11 and the exhaust gas aftertreatment device 12 connected thereto, such such as a catalytic oxidation catalyst and / or a diesel dust filter. Other elements of the exhaust tract are not shown.

Two exhaust gas recirculation lines 13, 14 are branched off from the exhaust lines 9, 10, in which two exhaust gas recirculation valves 15 are located (for example, pulse valves are only roughly marked), and two exhaust coolers 17 are located in the further exhaust gas recirculation line 16 gases. A common exhaust gas recirculation line 16 is connected to a boost line 6 downstream of a throttle valve made in the form of a controlled throttle valve 18.

In the exhaust tract in both exhaust lines 9, 10 (or alternatively directly in the exhaust manifolds 7, 8), upstream of the exhaust gas turbine 3b is located one jointly controlled by a servomotor 19 of a brake flap 20 of an industrial vehicle motor brake described below, which are controlled, respectively regulated depending on the electronic engine control unit 21 and the car control processor 22.

The gas exchange in the internal combustion engine 1 is controlled by the intake valves and exhaust valves of the valve timing mechanism (not shown), which additionally has a well-known EVB function, in which, as described at the beginning, an intermediate opening of the exhaust valves is initiated with a high backpressure of the exhaust gases and held due to the impact on the valve timing.

Motor braking by closing the brake flaps 20 and then activating the EVB function is initiated by the car control processor 22, for example, by a braking command from the driver and by the engine control unit 21 and is carried out by itself in a known manner, and the fuel supply is interrupted by a system not shown fuel injection.

If there is no braking signal for motor braking and the internal combustion engine 1 is in combustion mode (supplied with fuel under the control of the engine control unit 21, in accordance with the operating data of the internal combustion engine 1), the brake flaps 20 by means of a servo motor 19 under the control of the unit 19 engine controls are adjusted in their position so that, depending on the need, a certain exhaust backpressure is achieved, which sets either a quick warm-up to operating temperature in the case of a cold internal combustion engine 1, or a target exhaust gas recirculation rate by means of exhaust gas recirculation valves 15 in the case of a heated internal combustion engine 1.

For this, first of all, in the connecting line 23 between the exhaust lines 9, 10 upstream of the brake flaps 20 there is a pressure sensor 24, which constantly detects the actual value of the exhaust back pressure and which is capable of signal transmission connected to the engine control unit 21. Another pressure sensor 24 is provided in the boost line 6 downstream of the throttle valve 18. The corresponding pressure difference can be detected in the engine control unit 21 by means of both pressure sensors 24, and by means of a servomotor 19 can be set to a certain nominal value.

In addition, in the common exhaust gas recirculation line 16, in the boost line 6 downstream of the throttle valve 18 and in the intake manifold 25, temperature sensors are indicated by one position 26, which, in turn, are also able to transmit signals with the control unit 21 engine.

In the engine control unit 21, a characteristic is recorded for controlling the brake flaps 20 by means of a servomotor 19 in the combustion engine 1 of the internal combustion engine, which sets the optimum position for exhaust gas recirculation and / or accelerated heating of the internal combustion engine 1 in accordance with engine-specific data, such as engine speed, load, fuel injected, various temperatures received from temperature sensors 26, d pressure sensors 24 in the exhaust tract 9, 10 and the boost line 6, and also in accordance with the data of the processor 22 of the vehicle control, such as the position of the accelerator pedal, the current included gear stage, etc. In this case, the exhaust backpressure is constantly kept below a predetermined threshold value, which eliminates the operation of the EVB function.

In addition, an engine protection function is integrated in the engine control unit 21, which, in the case of unacceptably high, despite the fully open exhaust backpressure brakes 20, reduces the boost pressure in the boost line 6 by controlling the throttle valve 18 and / or reduces the power of the internal engine 1 combustion by reducing the amount of fuel injected. If necessary, bypass valves (bypass valve) provided in the exhaust duct can also be opened to reduce boost pressure.

The invention is not limited to the presented example of its implementation. Instead of a register pressurization system with exhaust turbochargers 2, 3, a simpler turbocharger system with only one exhaust gas turbocharger, with variable turbine geometry and, if necessary, only one exhaust line can also be provided if necessary.

In addition, it may be sufficient to control the degree of exhaust gas recirculation by means of exhaust gas recirculation valves 15 or to set a specific value for the increased exhaust gas pressure only with the help of the brake flaps 20, so that it may not be necessary to use a throttle valve 18 in the boost line 6.

The control of the brake flaps 20 in the combustion engine 1 of the internal combustion engine can be carried out in a simplified way only using the pressure sensors 24 or only using the characteristics recorded in the engine control unit 21 in accordance with the operating parameters of the internal combustion engine 1.

List of reference positions:

1 - internal combustion engine

2 - low pressure exhaust gas turbocharger

2a - compressor

2b - exhaust gas turbine

3 - high pressure exhaust gas turbocharger

3a - compressor

3b - exhaust gas turbine

4 - charge air cooler

5 - charge air cooler

6 - boost line

7 - exhaust manifold

8 - exhaust manifold

9 - exhaust line

10 - exhaust line

11 - exhaust line

12 - exhaust gas aftertreatment device

13 - exhaust gas recirculation line

14 - exhaust gas recirculation line

15 - exhaust gas recirculation valve

16 - exhaust gas recirculation line

17 - exhaust gas cooler

18 - throttle

19 - servomotor

20 - brake flaps

21 - engine control unit

22 - car control processor

23 - connecting line

24 - pressure sensors

25 - intake manifold

26 - temperature sensors

Claims (15)

1. A method for controlling at least one brake flap in an exhaust path of an exhaust gas-driven turbocharger, an internal combustion engine with at least one cylinder and a valve timing with an auxiliary brake function, wherein at least one exhaust valve is provided The exhaust gas back pressure brake flap can be moved to the intermediate opening position, as well as with a turbocharger connected to the compressor a boost line, to which, in addition, an exhaust gas recirculation line, controlled by an exhaust gas recirculation valve, connected to the exhaust path upstream of the brake flap, is connected, and the brake flap (20) is controlled to increase to a certain extent even in the combustion engine (1) exhaust gas counterpressure, characterized in that the exhaust gas counterpressure in the combustion engine (1) of internal combustion is constantly held below a threshold that prevents the auxiliary brake system (EVB) from tripping. 2. The method according to claim 1, characterized in that at least one brake flap (20) is located upstream of the turbine (2b, 3b) of at least one exhaust turbocharger (2, 3). 3. The method according to p. 1, characterized in that in the exhaust path (9, 10) upstream of the brake flap (20) there is a pressure sensor (24), the signals from which are sent to the control unit of the brake flap (20) (21) control, and it is preferably provided that when the exhaust gas backpressure is too high, despite the open brake flap (20), a controlled decrease in boost pressure and / or decrease in the amount of injected fuel is carried out. 4. The method according to p. 1, characterized in that a pressure sensor (24) is provided in the boost line (6), the signals from which are sent to the control unit (21) controlling the brake flap (20). 5. The method according to p. 3 or 4, characterized in that the signals of both pressure sensors (24) in the exhaust tract (9, 10) and in the boost line (6) are logically connected in the control unit (21) for the controlled installation of a certain pressure difference . 6. The method according to p. 1, characterized in that the brake flap (20) in the engine operating in the combustion mode is controlled depending on the operating parameters of the internal combustion engine (1) and / or depending on the instructions of the vehicle control processor (22). 7. The method according to claim 6, characterized in that in the engine control unit (21) in accordance with these data, a characteristic for controlling the brake flap (20) is recorded and the brake flap (20) is accordingly controlled, and / or in As operating parameters for controlling the brake flap (20), certain temperatures, and / or the amount of injected fuel, and / or the number of revolutions of the internal combustion engine, and / or the load load, are recorded and automatically processed in the engine control unit (21) STUDIO combustion. 8. The method according to p. 6, characterized in that the vehicle control processor is registered and used to control the brake flap (20) the position of the accelerator pedal, and / or the gearbox stage included, and / or the driver’s command. 9. A device for implementing the method according to any one of paragraphs. 1-8, for controlling at least one brake flap in the exhaust tract, including an internal combustion engine with at least one cylinder and a valve timing valve, equipped with a brake flap in the exhaust tract, pressurized by at least one exhaust gas turbocharger with an auxiliary brake function, in which at least one exhaust valve, when the exhaust gas backpressure is created by the brake flap, can be switched to The opening of the intermediate opening, as well as with the boost line connected to the turbocharger compressor, to which, in addition, the exhaust gas recirculation line is connected via the exhaust gas recirculation valve and connected to the exhaust duct upstream of the brake flap, the brake flap (20) located in the exhaust path (9, 10) upstream of the exhaust gas turbine (2b, 3b) of the exhaust turbocharger (2, 3), and may be driven by engine control lock (21) even when the internal combustion engine (1) is operating for a controlled installation of a certain exhaust backpressure, characterized in that the exhaust backpressure by the engine control unit in the internal combustion engine operating in the combustion mode is constantly kept below a threshold value , which eliminates the operation of the auxiliary braking system. 10. The device according to p. 9, characterized in that the actuation of the brake flap (20) is carried out pneumatically, hydraulically or preferably electrically by means of an appropriate servomotor (19). 11. The device according to p. 9 or 10, characterized in that the internal combustion engine (1) has a register boost system with a high pressure turbocharger (3) and a low pressure turbocharger (2), and the brake flap (20) is located in the exhaust path (9, 10) upstream of the exhaust gas turbine (3b) of the high pressure turbocharger (3). 12. The device according to claim 9, characterized in that in the case of an internal combustion engine (1) with several cylinders, two exhaust manifolds (7, 8) are provided with exhaust lines passing to the exhaust gas turbine (3b) (9, 10), and the fact that in each of the exhaust lines (9, 10) one brake flap (20) is installed, it is preferably provided that from both exhaust lines (9, 10) upstream of the brake flaps (20) one branch exhaust gas recirculation lines (13, 14) with a valve integrated in each of them ( 15) exhaust gas recirculation, which are brought together in at least one exhaust gas cooler (17) and connected to the boost line (6). 13. The device according to claim 9, characterized in that a pressure sensor (24) is located in the exhaust path (9, 10) upstream of the brake flaps (20) and / or in the boost line (6). 14. The device according to p. 13, characterized in that in the boost line (6) downstream of the means for influencing the boost pressure, there is a pressure sensor (24), it is preferably provided that the means for influencing the boost pressure is a controlled throttle valve (18). 15. The device according to p. 9, characterized in that at least in the at least one sensor (at least in the intake manifold (25) and / or in the boost line (6) and / or in the intake manifold (25) 26) temperature, which is connected to the engine control unit (21) in order to control the brake flaps (20).

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